Analysis of the decarburization and aging processes in 2 1/4 Cr--1 Mo steel
Specimens of 2$sup 1$$/$$sub 4$ Cr--1 Mo steel that had been decarburized in sodium or aged in an inert atmosphere for 26,500 h at 839$sup 0$K were metallurgically examined with optical and transmission electron microscopy. The carbide particle density of the decarburized and aged specimens was considerably less after 26,500 h than after 10,000 h, with the density in the aged specimen being considerably greater than that in the decarburized specimen. For the aged specimen, the density decrease was a result of Ostwald ripening, and the total amount of carbide was not noticeably affected. Decarburization, however, resulted in a gradient in carbide density, with the smallest density near the surface. Carbides were electrolytically extracted and identified by x-ray diffraction. From the before-test material, which was in the annealed condition and had a ferrite-pearlite microstructure, 1.4 wt percent carbide was obtained. This sample contained M$sub 3$C, M$sub 23$$C$$sub 6$, and M$sub 6$C, with M$sub 23$$C$$sub 6$ constituting the major portion. In the aged specimen, 2.3 wt percent of precipitate was extracted and contained 60 percent M$sub 6$C, the balance M$sub 23$$C$$sub 6$. The decarburized specimen contained two regions with different carbide contents. The first 20 percent of the 1.6 mm thick specimen yielded 1.3 wt percent precipitate, which contained 94 percent M$sub 6$C, the balance M$sub 23$$C$$sub 6$. The interior of the specimen contained 1.6 wt percent precipitate, 86 percent M$sub 6$C. (auth)
- Research Organization:
- Oak Ridge National Lab., TN
- Sponsoring Organization:
- USDOE
- NSA Number:
- NSA-33-015230
- OSTI ID:
- 4114674
- Journal Information:
- Metall. Trans., A, v. 6A, no. 11, pp. 2089-2093, Journal Name: Metall. Trans., A, v. 6A, no. 11, pp. 2089-2093; ISSN MTTAB
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360105* --Materials--Metals & Alloys--Corrosion & Erosion
AGING
DENSITY
HIGH TEMPERATURE
LIQUID METALS
LMFBR TYPE REACTORS
N50210* --Metals
Ceramics
& Other Materials--Metals & Alloys--Corrosion & Erosion & Surface Phenomena
REACTION KINETICS
SODIUM
STEAM GENERATORS
TIME DEPENDENCE
X-RAY DIFFRACTION